Baylor University, Royce-Darden Gospel Music Collection
This is still a work in progress at the Baylor University Libraries; the project's stated goal is to eventually have a copy of every gospel music recording from the 1940s-1980s digitized and catalogued. As of now, only 217 items (of an unspecified number) are available to the public, but I have the feeling Baylor faculty and students may be able to access more. Dr. Robert Darden, a professor of church music at Baylor, started the collection as a way to preserve "the Golden Age of Gospel Music" (so says the website), to bolster the school's fine arts library, and as a way of including Black Gospel music in the university's Baptist tradition. Students and scholars of church music, African-American history, or even pop music history might be able to use this as a resource. The collection also has its own blog, which tracks digitization progress.
Every available artifact having to do with a recording is scanned as images--the sleeves, liner notes, and the LPs--and clips of the audio are also available in mp4 format. The image scans are fairly high quality, and can be zoomed into for better looks at the detail. The clips probably are a means of protecting copyrighted material, since many recordings from this period aren't in the public domain yet. The collection is searchable, and users can also create a "favorites" folder in which they can compare and save items. Metadata includes the recording title, the artist or group, the publisher, the original format (LP, tape, etc.) and digital format, contents of the recording (i.e., the songs), and rights management; I took a look at the source code and it looks as though it was done according to Dublin Core standards, so there's a good range of interoperability there.